1. Field of the Invention
The present invention relates to an inspection apparatus, an inspection method, and a program.
2. Description of Related Art
In order to measure an accurate three-dimensional shape of a workpiece (inspection target product) by using a photometric stereo principle, there is required an illumination light source whose illumination light is incident on each surface of the workpiece with a uniform light amount. Further, an angle of incidence of the illumination light is required to be known. Moreover, since the angle of incidence of light should not change in accordance with a region of the workpiece, there is required an illumination light source having a size corresponding to the size of the workpiece to be inspected. Furthermore, scale information (actual dimension per pixel) of an image captured by a camera is also required. A visual inspection apparatus is often installed by a user, and it is difficult for the user to satisfy these strict installation conditions. Therefore, according to JP 2007-206797 A, a dedicated apparatus formed by integrating illumination and a camera is proposed, to thereby reduce a burden of installation of the user.
Incidentally, in order to generate an inspection image from a plurality of luminance images with respectively different illumination directions, a variety of control parameters are required to be set. For example, a light amount of the illumination light source, a shutter speed of the camera and the like are required to be appropriately set. The user checks a change in luminance image of the workpiece acquired by the camera while adjusting these control parameters, to search for appropriate control parameters.
However, since an inspection image used for inspection in the inspection apparatus is an image generated from luminance images by computing, even when the luminance images are checked, it is not easy to instinctively see whether or not the inspection image is correct. The inspection image may be displayed to allow the user to check the image, but even when an imaging condition is adjusted, the inspection image may not change in a manner easily seen instinctively. Therefore, even when only the inspection image is displayed, it may be difficult for the user to adjust the control parameter.